Thermometer



Oct. 18, 1932. C, F, CHAPMAN 1,883,554

THERMOMETER Filed Sept. 24, 1931 Patented Oct. 18, 1932UNITEDSTATESPATENT CHARLES F; CHAPMAN, OF HICAGO, ILLNQIS, ASSIGNOR TKRAFT-PHENlX-C'HEES' ILLINOIS, A CORPORATION on DELAWARE THERMOMTERApplication filed September rlhis invention relates to the vart of heatmeasuring instruments, having., reference more particularly, althoughnot exclusively, to thermometers'of that type which employ a bi-metallicstrip asthe heat sensitive agent to effect movements of a scale pointeror indi- Gator. The instrument forming the subject matter of the presentinvention has been designed more especially ture of liquids orsemi-liquids, and one obhas been to provide a re# ject of the Vinventionliable thermometer which may float on the surface of the liquid and doesnot require to*y be manually immersedk inthe latter-in order toaccurately indicate the temperature of the liquid. Another object is toprovide an in` strument of such construction as to eliminate thepossibility of broken glass or other for- 0 eign material being left inthe liquid in caseof the instrument being accidentally broken whileinservice. f

Other objects arev to provide an instrument readily adaptable to aninterchangeof dif' ferent scale dials, to provide4 an'instrument of the.encased type 'which maybe readily sealed against access of air at roomtemperature to the actuating element of the instru# ment, to provide,inl an instrument ofthis type, means and uniformly to the fun length ofthe` bi;

metallic actuator, to provide an instrument that may easily be movedover a tablev or other fiat surface, to provide an instrument whereinthe'transparent scale-covering disc or bezel shall be protected fromaccidental injury and from impairment of visibilitygby reason ofcondensed moisture within the case, and', generally, to provide animproved ther-A mometer of the type indicated-well adapted as a heatmeasuring instrumentl for -liquid and semi-liquid bodies on theflotation principle.

Still other objects and attendant advantages of the invention will beapparent to persons familiar 4with instruments of this type from thefollowing description, taken r,in connection with invention,andwherein-e' for indicating the tempera-- for transmitting the heatrapidly,

thel accompanying drawing in which I'have yillustrated one simple andpractical-mechanical embodiment of theV 24, 1931.y seriai'no. 564,880.

Fig. l is a top plan view. of the instrument. i

. Fig. 2 is a side elevation of the same. l Figl'isa vertical transversesection on the line 3f?) of Figs'. 1 and 4.

Fig. 4 is a plan section on Fig.k 3.` l Y j Fig. A5 is Va ldetailperspective view of the segment rack arbor and a radial arm associatedtherewith. y 4 Y 1 Y Fig. 6 is aV detail perspective view of a nut thatengages the threaded radial arm on the segment'rackarbor. Y 'j Y Fig.r7is perspective'detail viewofja'ball joint member that is mounted on thefree. endV y of the bimetallic actuator strip. Y* n Fig. 8 is a iperspective detail viewof a forked link and cooperating ball jointmember that connect the members shown in Figs. 6a`nd7. f

Referring to a shallow generally cup-shaped member forming the bodyportion of the case in which' the-parts of theinstrument are housed, and11'- designates asan entirety, a capv or cover member that is formedwith an inwardly offset de-v pending flange 12 that has a tight fit inthe top of the Vbody member 10; An hermetically sealed-joint is providedat this point by a film 'of shellac indicated at 13 between thecontacting surfaces'of the body member andk cover, for purposeshereinafter disclosed.

the imei-4er the drawing, 10 designates f other non-frangible material.`vThe marginal ortion of the disc 14 preferably*y underlies the cover11, andbeneath the marginal portionof the disc 14 is an. anglestripringl., kThecover 11, the disc 14', andthe horizontal limb of the ring15 are secured together by the threadedends 16 of a handle or bail17extendingtherethroughfand engaged4 by nuts 18,' and also by additionalshort bolts 19. A film ofL shellac 13 is also interposed between theadjacent surfacesY of the cover ll` and the bezel disc 14 to completethe sealing of the case. This bail 17 serves not only as. but also asV'a protecting bar to'prevent ac#v cidental injury to the disc 14. J AAttached by studsQO to the bottom wall of a handle,

25 (rig. 1).

the cup-shaped body l is a three-limb casting designated as an entiretyby 2l. The limbs of this casting are formed at their free ends withupstanding internally tapped posts 22, on which is secured, as by screw23, `a scale disc 24 provided witha peripheral scale Mounted on thecentral portion of the spider 21 is a frame comprising lower and upperplates 26 and 27 andspaoing posts 28, in whichframe is journaled anarbor29, the upper end of which extends through a hole in the dial plate24 and is equipped with the usual pointer 30, the tip of which playsover the scale 25. Also journaled in and between the frame plates 26Vand 27 isan arbor 3l that, as best Ashown in Fig. 5, is formed with ahub 32 carrying a radial screw threaded arm 33. Mounted on and securedfast with the upper reduced portion of the hub 32 is a segment rack 34(Fig. 4), that meshes with a pinion 35 fast on the pointer arbor 29. A

' spiral spring 36 anchored at one end to one of the bi-metallicactuator strip,

of the posts 28 and attached at its other end to the arbor 29 normallyurges the pointer 30 toward the low point of the scale, or against thepull of the actuator bar.

Cast integral with one of the posts 22 of the main spider 2l is a lug37, to the outer side of which is attached, as by screws 38, one endconsisting of two curved metal str ips having different coefficients ofexpansion, such as an inner strip 39 of brass and an outer strip 40 ofinvarsteel, soldered together. To the freeend of this strip areattached, as by bolts 4l, a pair of mating arms 42 formed with opposedrounded concave hands 43 (Fig. 7) that clampingly embrace theball-shaped hub 45 of a forked link 46, shown in ldetail in Fig. 8 themembers 43 and 45 thus forming a universal joint of the ball and sockettype. The limbs of the link 46 are flat steel springs and at their freeends are apertured, as shown at 47, to embrace opposite studs or pins 48that are formed on the four sides of a nut 49 (Fig. 6) that is mountedon the radial arm 33. The parts last described manifestly form aflexible universal joint connection between the free end of the actuatorstrip and the rod 33, through which, as the actuator strip expands orcontracts at temperatures above or below neutral (for example 80O thesegment rack 34 is turned, and the pointer 30 is moved forwardly orbackwardly over the scale. This flexible connection permits adjustmentof the nut 48 by a quarter turnor multiples thereof lengthwise of theradial arm 33, by which variations in the swing of the scale pointerunder a given expansion or contraction of the actuator strip may beeffect-ed, so that scale discs 24 carrying different scales such asFahrenheit, centigrade, etc., may be em-v ployed as desired. Theuniversal joint connection between the actuator strip and the link 46performs an important function in preventing the transmission to thearbor 31 of any warp or twist that may occur in the actuator strip, thusinsuring the free turning movement of the arbor 31.

Lying opposite the inner or concave side of the actuator strip,approximately parallel therewith and narrowly spaced therefrom, is a rib50 that is preferably integral with the spidericasting2land at its loweredge lies in contact with the bottom wall ofthe casing 10. The top edgeof this rib is substantially on a level with the top edge of theactuator strip. The heat of the material undergoing thermic measureimntis rapidly transmitted by conduction through the wall of the vessel 10to the rib 50, and thence by convection to the actuator strip,simultaneously and equally raising the temperature of the latterthroughout its full length, and thus reducing the lag to a minimum.

In an instrument of this type it is highly desirable to avoid thepresence of any moisture within the case, since, under low teinperaturesthe moisture may condense and cause rust to form on the arbors, as wellas cloud the under side of the transparent bezel disc and so impair thevisibility, and under high temperatures steam or vapor may form, withthe same objectionable consequences. Accordingly in the preferred andmost perfect form of the invention the case is filled with nitrogen orotherv moisture-free gas, such as carbon dioxide or air from which themoisture has been extracted by freezing, and this moisture-free gas isretained by the hermetically sealed joints 13 and 13. This can easily bedone, after the parts carried by the body and cover have been assembled,by simply assembling the body and cover in a bath of the moisture-freegas.

It will be observed that the transparent cover disc or bezel 14, thescale pl'ate 24, and the vertical limb of the ring l5 form a closedcircular chamber within which the pointer 30 and the upper end of itsarbor 29 are housed. y

The stationary and the spider 21 are preferably made of a light metal,such as aluminum, and the cas` ing is sutliciently large relatively toits weight, to4 cause the instrument to readily float even oncomparatively thin liquids. The instrument has been designed mainly tomeasure the heat of cheese during the sterilizing or blending processes,but manifestly it may be used to advantage in many other relations, suchas measuringthe temperature of water in a bathtub.

While I have herein shown and described one embodiment of the inventionwhich, in practice, has been found to satisfactorily effectuate the`stated, purposes and objects thereof, I donot limitA the invention tothe details shown and described,.but reserve such parts, such as thecasing 1. In a thermometer of the type described,

the combination with a case of heat'conducting material, of a scale, anindicator movable over said scale, movement multiplying mech'-anismconnected to said indicator and including anY arbor provided with aradial threaded arm, a nut on said arm, .a bi-metallic actuator stripsecured at one end by heat conducting' means Withink and to said case,and aV link` pivotally connecting the free end of said stripk and saidnut. i 2. In a thermometer oit the type described, the combination witha 4case'ofheat conducting material, of a scale, van indicator movableover said scale, movement multiplying mechanism connected to saidindicator, a bi-'metallic actuator strip secured at one end by heatconducting means Within and to said case, and a connection, including auniversal joint, between the Jfree end of said strip and an element ofsaid movement multiplying` mechanism.

3. In a thermometer of the type described, the combination With a caseof heat conducting material, of a scale, van indicator movable j oversaid scale, movement multiplying mechanism connected to said indicatorand cluding an arbor provided With a radial threaded arm, a nut on saidarm, a bi-metallicactuator strip secured at one end by heat conductingmeans Within and to vsaid case, and a'linl; having a universal jointconnection at one end to the free end of'said strip and pivotallyconnected at its other end to said nut. y 'Y 4l. In a thermometer of thetype described, the combination with acase of heatfconducting material,of a scale, an

over said scale, movement multiplying mechfall Within the spirit andpurtransparent indicator movable temperature variations transmittedthereto A through said case, said case having 1n itstop l c Wall a bezelof transparent non-frangible material overlying said indicating means,and a fixed handle bar spanning the topv of said case and orming'a guardfor said bezel.

7. In a thermometer of the type described,-

the combination With a case of heat conducting material adapted to floaton a liquid, ofmechanical y temperature indicating` meansr mounted insaid case, said means including a heat transmitting` rib lying inContact with a Wall of said case and disposed along Aside lof andnarrowly spaced :from said actuator strip.

8. In va thermometer of the type described,

lflexible bi-metallic actuator strip, and a fixed the lcombination Withan hermetically sealed case, of temperature-indicating means in saidcase, and a body of moisture-free gas filling said case.

9. Ina thermometer of the type described, the combination with a casecomprising av a cover having an hermetically Y body member, l sealedjointwith said bodyvmember, and a bezelhaving an hermetically sealedjoint with said cover, of temperatureindicating means in said case, anda body of moisture-free gasilling said case. Y

10. In a'thermometer of the type described, the combination With` agenerally cup-shape case of heat conducting materialadapted to float ona liquid, of a 'frame 4structure supported on the bottom Wall of saidcase, mechanical temperature-indicating means mounted on said framestructure, and headed studs attaching said frame structure to saidbottom wall, the heads of said studs forming glider feet to support theinstrument on a table or other fiat surface. i Y

CHARLES F. CHAPMAN.

anism connected to saidindicator and includl ing an arbor provided witha radial threaded arm, a nut on said arm equipped With a plurality ofpairs of radially opposed pins on its sides, a bi-metallic actuatorstrip secured at one end by heat conducting means Within and to saidcase, versal j ointV connection at one end to the free end of said stripand pivoted at its other end on a pair of said Vradiallyopposed pins.

5. In a thermometer, the combination with a case of heat conductingmaterial adapted to float on a liquid, of temperature-indicating meansmounted in said case and subjected to temperature variationsltransmitted thereto and a forked link having a uni-

